<!DOCTYPE html>
<html>
<head>
<title>HTML DOM Tree</title>
<meta name="description" content="Interactive diagram showing the structure of the HTML DOM of this HTML page." />
<!-- Copyright 1998-2016 by Northwoods Software Corporation. -->
<meta charset="UTF-8">
<script src="go.js"></script>
<link href="../assets/css/goSamples.css" rel="stylesheet" type="text/css" />  <!-- you don't need to use this -->
<script src="goSamples.js"></script>  <!-- this is only for the GoJS Samples framework -->
<script id="code">
  var names = {}; // hash to keep track of what names have been used

  function init() {
    if (window.goSamples) goSamples();  // init for these samples -- you don't need to call this
    var $ = go.GraphObject.make;  // for conciseness in defining templates

    myDiagram =
      $(go.Diagram, "myDiagramDiv",
        {
          initialAutoScale: go.Diagram.UniformToFill,
          // define the layout for the diagram
          layout: $(go.TreeLayout, { nodeSpacing: 5, layerSpacing: 30 })
        });

    // Define a simple node template consisting of text followed by an expand/collapse button
    myDiagram.nodeTemplate =
      $(go.Node, "Horizontal",
        { selectionChanged: nodeSelectionChanged },  // this event handler is defined below
        $(go.Panel, "Auto",
          $(go.Shape, { fill: "#1F4963", stroke: null }),
          $(go.TextBlock,
            { font: "bold 13px Helvetica, bold Arial, sans-serif",
              stroke: "white", margin: 3 },
            new go.Binding("text", "key"))
        ),
        $("TreeExpanderButton")
      );

    // Define a trivial link template with no arrowhead.
    myDiagram.linkTemplate =
      $(go.Link,
        { selectable: false },
        $(go.Shape));  // the link shape


    var nodeDataArray = [];

    // Walk the DOM, starting at document
    function traverseDom(node, parentName) {
      // skip everything but HTML Elements
      if (!(node instanceof Element)) return;
      // Ignore the menu on the left of the page
      if (node.id === "menu") return;
      // add this node to the nodeDataArray
      var name = getName(node);
      var data = { key: name, name: name };
      nodeDataArray.push(data);
      // add a link to its parent
      if (parentName !== null) {
        data.parent = parentName;
      }
      // find all children
      var l = node.childNodes.length;
      for (var i = 0; i < l; i++) {
        traverseDom(node.childNodes[i], name);
      }
    }

    // Give every node a unique name
    function getName(node) {
      var n = node.nodeName;
      if (node.id) n = n + " (" + node.id + ")";
      var namenum = n;
      var i = 1;
      while (names[namenum] !== undefined) {
        namenum = n + i;
        i++;
      }
      names[namenum] = node;
      return namenum;
    }

    // build up the tree
    traverseDom(document.activeElement, null);

    // create the model for the DOM tree
    myDiagram.model =
      $(go.TreeModel, {
        isReadOnly: true,  // don't allow the user to delete or copy nodes
        nodeDataArray: nodeDataArray
      });
  }

  // When a Node is selected, highlight the corresponding HTML element.
  function nodeSelectionChanged(node) {
    if (node.isSelected) {
      names[node.data.name].style.backgroundColor = "lightblue";
    } else {
      names[node.data.name].style.backgroundColor = "";
    }
  }
</script>
</head>
<body onload="init()">
<div id="sample">
  <h3>HTML DOM Tree</h3>
  
  <!-- The DIV needs an explicit size or else we won't see anything. -->
  <div id="myDiagramDiv" style="border: 1px solid blue; width:100%; height:300px"></div>
    <p>
        This sample shows the DOM (Document Object Model) of this webpage displayed as a tree.
        Each Node in the Diagram shows information about the corresponding HTML element in the DOM.
    </p>
    <p>
        When a node is selected, the background color of the corresponding HTML Element changes to lightblue.
        Below the diagram are some more HTML elements to illustrate the effect.
        This sample also makes use of the <a href="../intro/buttons.html" target="_blank">TreeExpanderButton</a>, 
        which allows for parent nodes to expand and collapse their child nodes. Buttons are defined in <a href="../extensions/Buttons.js">Buttons.js</a>.
    </p>
  <p id="lastParagraph">
    Elements with an id attribute are noted in parenthesis.
  </p>
  <div id="otherInfo">
    <div id="tableContainer" style="display: inline-block;">
      <table style="border: 1px; border-collapse: collapse;">
        <tr>
        <th id="firstHeader">Table header</th>
        <th id="secondHeader">Table header 2</th>
        </tr>
        <tr>
        <td>row 1, cell 1</td>
        <td>row 1, cell 2</td>
        </tr>
        <tr>
        <td>row 2, cell 1</td>
        <td>row 2, cell 2</td>
        </tr>
      </table>
    </div>
    <div id="listContainer" style="display: inline-block; border: 1px solid gray; margin-left: 10px; width: 100px">
      <p>My grocery list</p>
      <ul id="groceryList">
        <li>Coffee</li>
        <li>Milk</li>
        <li>Bread</li>
      </ul>
    </div>
    <p>
        For more uses of the <a>TreeLayout</a> see the <a href="DOMTree.html">DOM Tree</a> and <a href="visualTree.html">Visual Tree</a> samples.
    </p>
  </div>
</div>
</body>
</html>